The invention relates to a clamping tool, in particular a screw clamp having a fixed bracket, which provides a clamping surface and is fixedly connected to a slide rail on which a sliding bracket is seated such that it can be displaced and secured, and having a counter clamping surface which, by means of a clamping element, can be braced against a workpiece which can be clamped in between clamping surface and counter clamping surface, the eyelet of the sliding bracket being secured against slipping with respect to a profiled slide rail.
Different embodiments of such clamping tools, in particular screw clamps, for example in the form of so-called all-steel screw clamps or screw clamps with a steel section slide rail and malleable-cast-iron brackets, are known. Among these embodiments, there are also known those which have a device for securing the sliding bracket against slipping with respect to the slide rail. For this purpose, the sliding bracket tilts when a workpiece is clamped with respect to the fixed bracket, as a result of which the sliding bracket is fixed in place. In this respect, it is also known to profile the slide rail. A further embodiment of the antislip device is known from DE-A1 32 18 486. In order to secure the sliding bracket against slipping, this document provides a threaded pin which is positioned such that it projects into the eyelet of the sliding bracket to a slight extent. If the sliding bracket tilts with respect to the slide rail during clamping of a workpiece, then the threaded profile of the threaded pin is pressed against the outer narrow side of the slide rail in order to prevent the sliding bracket from slipping under the action of the clamping forces.